Irrumatio
by izzygone
Summary: Castiel is still relatively new to this whole practically-human vessel-only existence but he's pretty sure his obsession with Dean Winchester's mouth is perfectly normal.


Castiel is still relatively new to this whole practically-human vessel-only existence but he's pretty sure his obsession with Dean Winchester's mouth is perfectly normal.

Really, how could anyone do anything other than stare when Dean does that thing with his tongue against his teeth when he talks or the way he bites his lip when he's focused on research or when he runs his tongue over his top lip after a particularly good bite of pie or the way he pouts when his brother is insolent or how his teeth show white against the flushed pink of his lips when he laughs or –

So maybe Castiel's obsession is a little beyond the normal. But it's not that big of a deal. It's not like Dean notices or cares and as far as addictions go, it's a pretty benign one.

Though admittedly it's potentially problematic when seeing Dean's lips wrapped around the lip of a beer bottle makes his mind go a little blank or when he realizes he enjoys watching Dean's lip quiver so much he's willing to hurt him just to see it.

Okay, so it's a bit more than your average addiction, but he's managing it. Sometimes he takes little breaks, stays away from Dean so long it starts to build like a pressure in his insides, makes him feel like exploding with his need to catch Dean's lip with his teeth, taste the tanginess of his saliva, feel tongue against tongue. But Castiel knows it's for the best and that with time, it will get better and he'll want to touch a little less, he'll want to hurt Dean a little less.

But every time he goes back, every time he responds to Dean's desperate pleas, it's just worse. Dean smiles or licks his lips or swallows hard and Castiel just wants to _hold him down_ and do the kinds of things he has observed human men do to women for thousands of years.

Instead he clenches his fists, acts like he's angry, acts like Dean is some kind of inconvenience. But really it's Cas who's the inconvenience. It's his stupid human vessel, this human body filled with base desires and lack of self-control.

Which is probably why he responds to Dean one night when he really shouldn't. When he knows Dean isn't in trouble, he's just drunk and thinking about Cas, wondering here his righteous best friend is, wondering why he hasn't seen the angel in, _god_, how many weeks?

And then Cas is watching from a few feet down the alley as Dean stumbles along, bottle in one hand, limping just a little from a wound he took years ago that has long since healed and his body forgets until he's tired or shaking with drink. Cas knows Dean is crying, that the alcohol has dulled the hunter's senses which is why he drinks like he does – so he can just fucking let go sometimes.

And Cas can't stop himself, he has to get in front of Dean, has to see the tears stream over those lips, has to run his fingers across them, pick up those tears and swallow them.

Dean looks vaguely surprised as Cas materializes two feet in front of him but recovers quickly. He reaches forward and Cas stands perfectly still as Dean's hand connects gently with his elbow.

"Cas," Dean breathes, a little disbelieving, simultaneous with a smirk sliding onto his mouth. Like maybe he knows Cas can't resist him.

"Dean." There's a warning to his tone. It should be: _I don't like to be called for trivial matters_ but it's really: _Be careful because I don't know what I might do to you right now_.

But Dean just smiles, brings the bottle to his mouth and Cas stares as Dean's throat works the liquid down, his adam's apple bobbing suggestively and Cas tries to swallow and not think about his own newly human throat and the sensation of thirst.

Dean chugs the whole bottle – whiskey, it looks like though Cas is looking at the back of the label through the glass and doesn't really know for sure – his lips tight around it like it contains mana from heaven. Cas wants to yank it away, replace it with his fingers.

When he's finished, tossing the bottle away, Dean licks his lips.

Of course he does.

Because he's trusting Cas not to do something fucking stupid and selfish and base like growl and grab Dean so hard by the shoulder that he might be already bruised and pull him close enough to smell the liquor on his breath.

"Dean." He says again, but this time it's something savage and it should make Dean pull away disgusted and angry but instead it makes him suck on his bottom lip, grunting out a quiet mocking _hmmm_?

And that's all it takes to make Cas push Dean onto his knees and free his damned human cock from the trousers it seems like he's been wearing his whole life.

Dean should resist, but he doesn't. He leans forward, presses an impossibly chaste kiss to the head of Castiel's full cock without any further encouragement.

Cas is an angel, but his vessel needs blood and it's all drained straight to his cock in such a rush, he feels dizzy and a little drained. And Dean's tentative and teasing presses of lips to dick is not enough.

Cas shouldn't, but he's already this far and he needs more and he might be more deserving of hell than Lucifer so he grabs the back of Dean's head, human fingers twisting into Dean's hair, forcing him forward to take more of Castiel's cock.

Dean hums but doesn't pull back, just opens his mouth wider and runs his tongue on against the underside of Castiel's shaft.

Cas has thought about this a thousand times – maybe more – and all of those thoughts combined could not compare even by a fraction to the feeling of _this_. This hot, wet perfection. And Dean is not idle, his slick tongue moving back and forth underneath Cas' stupid, impulsive, controlling, hot, hot _perfect_ human cock, but Cas can't help himself, he rocks forward, shoving himself against Dean's throat. Dean doesn't gag – he should, but he doesn't, like maybe he's been practicing his whole life for this moment – he just swallows around the intrusion and hums like it's fucking perfect, like he fucking _deserves_ this.

And that just makes Castiel angrier because, _fuck_, Dean deserves better than this. He deserves tenderness and compassion and to be made sweet, slow love to. But Cas has no patience and he wants more, so much more and he knows in that moment that Dean would give it to him. Because Dean thinks he deserves this torture.

Dean is gripping Cas' legs, holding himself up and holding on like he might slip away if Cas moves. He digs his fingers in, almost enough to tear the fabric of the khaki pants Cas never bothered to change out of. It hurts Cas a little, and then a lot because Cas is letting his vessel feel for the first time in a long time and in order to feel the pleasure of taking Dean like this, he must also feel the pain.

And even though he knows he shouldn't, Cas is holding Dean in place with his human hand firmly in place at the back on Dean's fragile human skull as he cants roughly forward and it must burn and he can see tears pooling in the corner of Dean's eyes. And, fuck, he can hear Dean, hear him moaning _Cas, Cas, Cas_ over and over again in his mind, a little prayer that lets the angel in.

But Cas doesn't feel like an angel. He feels like a demon, like something evil using Dean for his own pleasure but he can't, he _can't_ stop. All he sees are Dean's lips around his swollen cock, taut and red and sore and just fucking begging for him to continue. And Dean lets just to ridge of his teeth graze the underside of Cas' cock and it hurts but it feels so damn good because that's what Cas deserves – _pain_, pain inflicted by the gorgeous man below him. And then Dean is slurping and sucking and he's a hot mess and looking more and more abused and debauched and it only makes Cas harder and hotter.

Dean swallows, and Cas can actually _feel_ the sensation of Dean's throat swallowing around him, and he feels Dean let go of one of his legs, reaching down and freeing himself from his jeans, his filthy, alley-mud covered jeans. Dean pulls out his own cock, and it's hot and erect and Cas is familiar with it because he once snuck invisible into Dean's room late at night and jerked him off slowly in his sleep, and thinking about that moment pulses a flare of guilt through him. He's angrier with himself than with Dean, he knows he's to blame for every fucking thing, but he wants to take it out on Dean. He wants to make Dean suffer for this infection of sin in his grace.

Dean palms himself, picking up precome on his palm and then he's wrapping his fingers in a tight fist around his own cock, pumping up and down in rhythm with Cas' quick and rough movements. It makes Cas hot and guilty that Dean is getting off to this, getting off to being abused but he can't stop from thinking how ungodly sexy it is. Dean moans aloud at his own touch and he's still praying to Cas but now he's thinking other things besides the angel's name. Things like _I want you to come in my mouth_ and _that__'s right, fucking use me_. And that's just about enough to knock Cas over because _how fucking sexy can one man be?_ but instead Cas is coming, and he nearly falls forward with the surprise of it. Dean swallows right through it, drinking Cas down like he's been thirsty for it his whole life and he strokes himself harder, and Cas thinks it must hurt a little but then Dean is coming, too, all over his dark and ruined jeans.

Cas steps back, carefully tucking himself away. Dean is looking up at him, lips swollen and bruised and they've never looked more perfect. Cas runs his fingers over them, and Dean whimpers, slipping his tongue out to taste Cas' finger. Cas thinks he could go again, right there, right then because _fuck_, Dean has the perfect mouth. But he doesn't. He may behave like a monster but he isn't one. Instead of grabs Dean by the arm and pulls him up. Dean falls forward against him, sobbing, and Castiel knows it's time to bring him home.

A/N: The title actually means "to thrust the penis into the mouth." Education xoxo ;)


End file.
